Revert an unintentional API ABI break

[aprantl]

Summary

lldb::LanguageType is used as a parameter in SBExpressionOptions::SetLanguage(), which actually makes this type API too. Commit 6eaedbb52f2a616e644e5acc7279c8b07c4cfe82 added a : uint16_t to it, which broke binary compatibility for the SBAPI. This patch reverts to the original enum.

I tried moving the entire enum into include/API, but that created a cyclic module dependency between API and Utility. To keep things simple, this just reverts to the original code and adds a warning.

[JDevlieghere]

Ship it

lldb/include/lldb/lldb-enumerations.h

FLAGS_ENUM(WatchpointEventType){
     eWatchpointEventTypeTypeChanged = (1u << 12)};
 
 /// Programming language type.
 ///
 /// These enumerations use the same language enumerations as the DWARF
 /// specification for ease of use and consistency.
 /// The enum -> string code is in Language.cpp, don't change this
 /// table without updating that code as well.
-enum LanguageType : uint16_t {
+///
+/// This datatype is used in SBExpressionOptions::SetLanguage() which
+/// makes this type API. Do not change its underlying storage type!
+enum LanguageType {
   eLanguageTypeUnknown = 0x0000,        ///< Unknown or invalid language value.
   eLanguageTypeC89 = 0x0001,            ///< ISO C:1989.
   eLanguageTypeC = 0x0002,              ///< Non-standardized C, such as K&R.
   eLanguageTypeAda83 = 0x0003,          ///< ISO Ada:1983.
   eLanguageTypeC_plus_plus = 0x0004,    ///< ISO C++:1998.
   eLanguageTypeCobol74 = 0x0005,        ///< ISO Cobol:1974.
   eLanguageTypeCobol85 = 0x0006,        ///< ISO Cobol:1985.
   eLanguageTypeFortran77 = 0x0007,      ///< ISO Fortran 77.